Re: [PATCH] xfs: report a writeback error on a read() call

[Yafang Shao]

> That's really kernel wide policy and not something magic done by a
> single file system.

XFS already supports an optional policy for handling metadata errors via:
/sys/fs/xfs/<disk>/error/metadata/

It would be reasonable to introduce a similar optional policy for data 
errors:
/sys/fs/xfs/<disk>/error/data/

This data error policy could allow the filesystem to shut down 
immediately if corrupted data is detected that might otherwise be 
exposed to userspace.

While it’s unclear whether such a policy should be implemented at the 
VFS level as a kernel-wide mechanism, we can certainly extend the 
existing XFS error-handling framework to support it. In other words, 
this would be a natural extension of current XFS functionality—not a 
reinvention.